1. Field of the Invention
The present invention relates generally to a library apparatus for use in storage, recording and reproduction of recording media such as magnetic tapes accommodated in a cartridge, and more particularly, to a library apparatus for cleansing the recording media within the apparatus and a control method thereof.
2. Description of the Related Art
Library apparatuses have hitherto been used to store magnetic tapes acting as recording media, load the magnetic tapes into a recording/reproduction device of the apparatus and write or read data. Cartridge recording media are magnetic tapes in cartridge form. A dirty magnetic tape can lead to deteriorated data recording/reproduction characteristics such as lower data read or write accuracy and dropouts, and therefore its cleaning is essential.
Japanese Patent Application Laid-Open Publication Nos. 10-64241 and 06-168425 are among related technical patent documents regarding such magnetic tape cleaning.
In the cleaning apparatus and cleaning method disclosed in Japanese Patent Application Laid-Open Publication No. 10-64241, a cartridge is provided with two cleaning tapes, and, with a magnetic tape sandwiched between the cleaning tapes, the magnetic tape and the cleaning tapes are run at different speeds, thus cleaning the magnetic tape.
In Japanese Patent Application Laid-Open Publication No. 06-168425, on the other hand, an apparatus, designed to restore the magnetic head of a magnetic recording/reproduction device to normal function and give a warning properly in the event of a failure, is configured to detect the amount of wear and degree of dirt on the magnetic head, giving a warning and loading a cleaning tape into the magnetic recording/reproduction device in response to the detection result.
Incidentally, description will be given of magnetic tape loading in a library apparatus with reference to FIG. 1. FIG. 1 shows a recording/reproduction unit of a library apparatus.
In a library apparatus 2, a plurality of recording/reproduction devices 4 are provided that are designated, for purposes of description, at #0, #1, #2 and #3, as the order of loading. Indicated by “6” is a magnetic tape as a tape medium loaded into the recording/reproduction devices 4, whereas a cleaning tape for cleaning the recording/reproduction devices 4 is indicated by “8.”
In reading data of the magnetic tape 6, if the data recording surface of the magnetic tape 6 is dirty, and if the dirt is caused by adherence of dust, loading of the magnetic tape 6 into the recording/reproduction device 4 (#0) will result in the dust adhering to the recording/reproduction head of the recording/reproduction device 4 (#0) from the magnetic tape 6. Continued use of the recording/reproduction head, with dust attached, will make it impossible to read data from the magnetic tape 6 in the middle of the process, resulting in data check error. Because it cannot be determined whether the error is attributable to the magnetic tape 6 or the recording/reproduction device 4, the magnetic tape 6 is ejected from the recording/reproduction device 4 (#0) in the middle of the process and reloaded into the recording/reproduction device 4 (#1). If the magnetic tape 6 is dirty, the recording/reproduction head of the recording/reproduction device 4 (#1), into which the magnetic tape 6 is reloaded, will become dirty, resulting in the magnetic tape 6 being ejected again. If data reading is resumed, the magnetic tape 6 will eventually be removed from the library apparatus 2, after repetitions of loading and ejection, as a defective medium that cannot be handled. In arrows “a”, “b”, “c” and “d” shown in FIG. 1, “a” indicates loading of the magnetic tape 6, “b” ejection, “c” removal and “d” loading of the cleaning fane 8.
Removal of the magnetic tape 6 from the library apparatus 2 as a defective medium following these processes delays a judgment as to whether the magnetic tape 6 is usable. Besides, the process time for removal from the library apparatus 2 is long and wasteful. If the magnetic tape 6 is loaded into the three to four recording/reproduction devices 4, the dirt of the magnetic tape 6 will transfer, contaminating the recording/reproduction heads. If the cleaning process of the recording/reproduction heads of the recording/reproduction devices 4 (#0 to #3) is conditioned by the running distance, the cleaning tape 8 cannot be loaded even when the recording/reproduction head is dirty, unless the running distance does not reach a given distance.
Thus, with regard to the problem of avoiding inconveniences such as dirt on the magnetic tape contaminating the recording/reproduction heads of a plurality of recording/reproduction devices and delayed judgment as to whether the magnetic tape is usable, there is no disclosure or suggestion thereof in Japanese Patent Application Laid-Open Publication Nos. 10-64241 and 06-168425, nor is there any description of means for solving the problem.